27-inch iMac EFI FW Update
You can download 27-inch iMac EFI FW Update 1.0 for Mac from our software library for free. 27-inch iMac EFI FW Update for Mac lies within System Tools, more precisely System Optimization.
From the developer:
27-inch iMac EFI FW Update is recommended for all quad-core Intel Core i5 and Core i7 processors 27-inch iMacs. The app solves an issue that sometimes caused high processor utilization while playing audio through the headphone output mini-jack. In addition, it solves an issue that prevented the display backlight from turning on after powering on the iMac.
You may want to check out more software for Mac, such as MacBook EFI Firmware Update, Mac mini EFI Firmware Update or iMac Graphics Firmware Update, which might be related to 27-inch iMac EFI FW Update.